Question

The value of g at the surface of earth is
9.8 m/s2. Then the value of 'g' at a place 480 km
above the surface of the earth will be nearly (radius
of the earth is 6400 km)
(1) 9.8 m/s2
(2) 7.2 m/s2
(3) 8.5 m/s2
(4) 4.2 m/s2​

Answer 1

Answer:

M= mass of earth

R= radius of earth =6400km=6.4×10

6

m

g

1

= acceleration due to gravity on the surface of earth =9.8m/s

2

h= height above the surface of earth 480km=0.480×10

6

m

g

2

= acceleration due to gravity above the surface of earth=?

acceleration due to gravity on the surface is given

g

1

=

R

2

GM

----------------------------(1)

acceleration due to gravity above the surface is given:

g

2

=

(R+h)

2

GM

------------------(2)

g

1

g

2

=

R

2

GM

(R+h)

2

GM

g

1

g

2

=

(R+h)

2

R

2

9.8

g

2

=

((6.4×10

6

)+(0.480×10

6

))

2

(6.4×10

6

)

2

g

2

=8.5m/s

2

.

Answer 2

Answer:

option c . 8.5 m/s2 is the correct one .